Around one in six people in London and one in 20 elsewhere in England have already had the coronavirus, the United Kingdom's Health Secretary Matt Hancock said, as he announced plans for "antibody certificates".

Data gathered from an antibody surveillance study suggests 17 percent of people in London and around five percent of people across England have tested positive for antibodies to coronavirus, he told the daily Downing Street briefing.

More:

This news comes as the government agreed to a deal with pharmaceutical firms Roche and Abbott for more than 10 million antibody tests, to see if people have had COVID-19.

They will first be offered to health and social care staff as well as patients and care home residents.

UK's divided response: Varied messages across four nations [2:43]

The tests are not without their critics. Germany, one of the first countries to order millions of tests from Swiss drug giant Roche, said it would not use them until they had been debated by the country's top ethicists.

Concern remains about how the issuing of "antibody passports" could lead to a two-tier society, with some people continuing to be locked down at home while others move about freely with life beginning to return to normal.

"In our view, any documentation that limits individual freedoms on the basis of biology risks becoming a platform for restricting human rights, increasing discrimination and threatening - rather than protecting - public health," read an editorial comment in top science journal Nature.

The level of immunity remains a mystery, wrote Nature's editorial board. Tests are unreliable, the volume of testing needed is unfeasible and the threats to privacy and marginalised groups who would likely face even greater scrutiny all mean that immunity passports are a bad idea, they wrote.

The UK government is, however, seemingly pressing on regardless, and also arranging supplies for the devolved administrations of Wales, Scotland and Northern Ireland, with each part of the UK deciding how to use its test allocation.

Syrian refugee’s message to Boris Johnson [1:54]

While it remains unclear what level of immunity people develop once they have had COVID-19, some experts hope a degree of immunity lasts for at least a year or two.

However, having antibodies does not automatically mean a person will not pass the virus onto somebody else.

Hancock said: "This is an important milestone and it represents further progress in our national testing programme. Knowing you have these antibodies will help us to understand in the future if you are at lower risk of catching coronavirus, dying from coronavirus and of transmitting coronavirus."

Testing times

Hancock also announced a trial of a rapid 20-minute test to tell people if they currently have COVID-19 following criticisms that people have been waiting days or weeks for test results.

Accident and emergency hospital departments, general-practitioner testing hubs and care homes in Hampshire will all trial the new test, which will be used on up to 4,000 people.

The test does not need to be sent off to a lab and will be rolled out more widely if it is shown to be effective, Hancock said.

Can apps put coronavirus in check? | Inside Story [24:42]

Before the press briefing, Downing Street announced a U-turn on the National Health Service surcharge, saying overseas health and care staff would be exempted from the fee levied on migrants to pay for the NHS.

It came after mounting pressure on Prime Minister Boris Johnson from senior Tories, with former party chairman Lord Patten calling the charge "appalling" and "monstrous".

Labour leader Sir Keir Starmer, who urged the prime minister in the Commons on Wednesday to scrap the charge, said: "Boris Johnson is right to have U-turned and backed our proposal to remove the NHS charge for health professionals and care workers.

"This is a victory for common decency and the right thing to do. We cannot clap our carers one day and then charge them to use our NHS the next."

The decision came a day after another U-turn, when the government extended a scheme offering indefinite leave to remain in the UK to the families of all immigrant NHS staff who die as a result of contracting coronavirus.

Certificates

At the daily press briefing, Hancock said certificates were being looked at for people who test positive for coronavirus antibodies.

He said: "It's not just about the clinical advances that these tests can bring.

"It's that knowing that you have these antibodies will help us to understand more in the future if you are at lower risk of catching coronavirus, of dying from coronavirus and of transmitting coronavirus.

"We're developing this critical science to know the impact of a positive antibody test and to develop the systems of certification to ensure people who have positive antibodies can be given assurances of what they can safely do."

Meanwhile, England's chief medical officer Professor Chris Whitty told the briefing the total number of deaths from all causes was now down to the rate in an average winter.

He said "All-cause mortality has come down at the same time as the COVID deaths have come down, and it is now at roughly the rate it is at in an average winter.

"So, we are essentially having a winter in health terms, in terms of mortality, but in late spring and early summer."

Prof Whitty also said care home deaths had peaked and have now come down.

On the test, track and trace strategy, Hancock sought to play down the importance of the delayed app in the contact tracing process.

He had originally said the app would be rolled out by mid-May, but it has now been delayed by several weeks.